Method of making endless belts



. Fawn 1941- A. auzmu. arm. 33, 94

METHOD or MAKING ENDLESS BELTS; Original" Filed April s0, 19 32 7 I'IL/EfiZbEE 491/527 .5 175557]! 5205572 E si 541 552 Patented Feb. 25, 1941 UNITED STATES PATENT OFFICE METHOD OF MAKING ENDLESS BELTS Allan B. Merrill and George H. Stewart, Akron, Ohio, assignors to The B. F. Goodrich Company, New York, N. Y., a corporation of New York Claims.

This invention .relates to endless power-transmission, belts and is of especial value in trapezoidal or V-type belts. This is ,a division of our copending application Serial No. 608,483, filed April 5 30, 1932, now Patent No. 2,029,381 of February 4,

The chief objects of the invention are to provide efficiency of power transmission and to provide a belt adapted to give long service.

We find that these objects are attained to a surprising extent by the belt of the present invention.

Of the accompanying drawing:

Fig. 1 is an elevation of a strand of belt-core material arranged to illustrate one of the features of the invention. v

Fig. 2 is a perspective view of a portion of one of the belt cores.

Fig. 3 is a perspective -'iew of a portion of the finished. belt.

Referring to the drawing, the. belt in its preapart, in a cushion body of; rubber H- which corn pletely-ginsulates them" froml a. two-ply',';weak

the cushion body I.

weftedj'orzweftless cord-fabriccover IZ' enclosing- V to eaehj flth driving faces of the belt to permit thewus fofTthe 'non fibrous rubber body II, for highfixibility and avoidance of heat generation, .35

Thecoverffabric isso appli'edtin"thispreferred" 35. embodi n;en't-. 'th-at itsfstrength-giving cords, l3,

l a xt elfld obliquely, with the cords. of one ply cross 'ggthose" ofv the other fo'r efficienttransmission, of -the driving force from: the-radially remote portions o f thegpulleygroove walls to the cores IO'; mat the drivingpulley andfrom the cores Ill, ID to the radially: remoteportions of,

the pulley-groove ,walls at the driven pulley.

Each of the cores I0 is preferably formed, as

shown in Fig. 1, by arranging an end portion of.

5 a cord in the form of a circle to provide a winding form and then winding the cord helically upon the circularly arranged portion, in a plurality of helical courses, until a core of the desired strength is obtained.

50 Preferably the stretchability of the cord is reduced before it is wound into the core, as by wetting it and drying it under tension, and the wetting preferably is effected by the use of a natural or artificial aqueous dispersion of rubber,

55 so that the drying coagulates a deposit of rubber in the interstices of the cord and provides a desirable rubberizing of the cord, in conjunction with the setting of the cord in its elongated condition.

The cover conveniently may be applied in known types of ring-covering machines. I

When the belt has been assembled in substantially the form shown in Fig. 3 it is vulcanized under longitudinal tension and transverse pressure in a mold to produce the finished, vulcanized belt of Fig. 3.

It is believed that the remarkably high powertransmission efllciency and corresponding long life of the belt, especially under heavy load and at high speed, are attained by reason of high flexibility combined with high resistance to stretch,

both of which are opposed to destructive absorption of power in the material of the belt and such as occurs when a strong force is necessary for bending a belt into conformance with the 20 pulley or when a belt undergoes a high percentage of stretch in passing from. the driven pulley into the drive reach and then correspondingly shortteem passing from the drive pulley into the slack or return reach. 2 {flTh'characteristics of high flexibility and resistance to stretch are contributed to by the use ,of'a plurality of the cores, which permits an adefouate'a mount' of the strength-giving core matelb ef localized in the neutral zone of the 30 d theplurality of cores also provides strength-givingcore, material 'sufilciently close throughout a large portion of the cross-sectional arrangement/offthe, core i naterial also assures efficient transmission ofjforceffrom the cover to 40 the core material even thought e lit 01' the belt in the pulleygrooveislmperfect r The 'cabled tructureof thefico es givesthem high flexibility "conjunctiori' "with: strength, especially when a plurality of them; are employed, so that each'may be'ofi small 'diameteriand con sequently not be required to ex'tendfarineither direction radially from the neutral axis or that part of the belt which neither'elongates nor contracts longitudinally in the running of the belt onto or off of the pulley.

Flexibility in conjunction with strength against power-consuming and destructive stretch also is contributed to by the weak-wefted or weftless cord-fabric cover, which is adapted to be easily shown in the drawing is that it provides such 01 the belt is caused by transmission of the load proximity of each core to the adjacent driving face of the belt that but little flexing of the rubber between each core and the adjacent driving face from the face to the core. In other words, there is 1 but little longitudinal shift of the relative positions of the cores and cover as the belt enters and leaves the tensioned reach, thus internal heating is greatly reduced.

Also, the two core construction with the flexible rubber body'permits lateral rotative self adiustment of the belt in its groove to anextent sumcient to accurately distributethe load between the two cores without destructive internal friction when the cores vary slightly in circumierence, and thereby prevents overloading of an individual core.

While we have here shown and described the preferred embodiment of ourvinventiomvarious modifications are possible without sacrifice of all 0! the advantages of the invention and within the scope of the appended claims. w

Weclaim: 1., The method of making an endless transmission belt which comprises wetting a. cord, drying I it under tension to reduce its extensibility; im"--. pregnating it with a rubber compound, arranging an end portion thereof in the form of a loop, and M ,I e

winding the remainder of the cord on the loop so formed in a plurality of helical courses to provid an endless cabled core. l, g

2. The method of making an endless transmission belt which comprises wetting a cord with an aqueous dispersion of rubber, drying it under ten- I sion .to reduce its extensibility, arranging an end portion thereof in a loop, and winding the remainder of the cord on the loop so formed in a plurality of helical courses to provide an endless cabled core.

3. The method of making an endless transmission belt which comprises wetting acord with an artificial aqueous dispersion of rubber, drying it under tension to reduce its extensibility, arranging an end portion thereof in a loop, and winding the remainder of the cord on the loop so formed in a plurality of helical courses to provide an endless cabled core.

4. The method oi making an endless transmission belt which comprises wetting a. cord while impregnating it with rubber, drying the cord under tension to reduce its extensibility, forming a plurality of endless grommets therefrom, each comprising a plurality of integral helical courses cabled together under tension, and arranging the grommets in parallel spaced relation in a body comprising rubber material.

5. The method of making an endless transmission belt which comprises wetting a cord with an aqueous dispersion of rubber, drying the cord un der tension to reduce its extensibility, forming a comprising a. plurality of integral helical courses cabled together under tension, and arranging the grommets in parallelspaced relation in a body 7 comprising rubber material.

ALLANB. MERRILL. GEORGE H. STEWART.

. plurality or. endless, grommets therefrom each 9 

